1. Field of the Invention
The present invention relates to a control device, in particular for a domestic appliance. Further, the present invention relates to a button panel for said control device. Moreover, the present invention relates to a method for assembling a control device, in particular for a domestic appliance.
2. Description of the Prior Art
An appliance includes often a control device with one or more touch switches. For example, said touch switches may be of a capacitive type, an inductive type, an optical type, an infrared type or a funk type. In other words, the touch switches do not contain any mechanical elements. None of the components of the touch switches is distorted. The touch switches of the control device of an appliance, in particular of a domestic appliance, should be illuminated in order to indicate the corresponding operation and/or a parameter relating to said switch or corresponding operation. Further, the illumination should also be sufficient, if the environmental illumination conditions are disadvantageous. For this purpose, known touch switches are lightened by illumination means.
Furthermore, another problem is that the illumination of a switchable area of the switch is not homogeneous enough. Some parts are intensively illuminated, while other parts are quite dark, since touch switch may include one or more electrical tracks arranged on the printed circuit board. Said electrical tracks are usually made of copper or other opaque materials. In particular, the electrical tracks of the touch switch are provided as sensor for detecting the proximity or touch of a human finger. Further, the electrical track may be provided as antenna for detecting infrared or radio signals. However, the electrical tracks may cross the illuminated area of the touch switch and constrain the illumination. Such a design is even more complex and expensive and results in higher energy consumption, since some light is absorbed by a switchable area.
EP 1 985 930 B1 discloses a control device with a front panel for a domestic appliance. At the rear side of the front panel are one or more switches having at least one illumination element. The front panel is made of transparent glass or plastics with printed icons. The illumination element consists of at least one light source element arranged on the rear side of a printed circuit board and at least one reflector element for indirectly lightning of a rear side of the switch. The reflector element covers the light source element and the illuminated area from behind. The control panel must be of a transparent material in order to allow the light passing through at least a part of the switchable areas. However, it is difficult to find any suitable material for a button panel, which is transparent on the one hand and able to carry electric and/or electronic components. Further, the control device has a complex design, so that the costs for the illumination of the switch are relatively high. In particular, the costs of a transparent material for the button panel and printed circuit board are high.